build: Fix out of tree builds Adding local-link.h as private header file requires $(srcdir) on AM_CPPFLAGS to be found by generated sources when builddir != srcdir. Do not use libmd.sym from $(srcdir), as it is a generated file. [guillem@hadrons.org: - Remove unrelated line moves. ] Signed-off-by: Guillem Jover <guillem@hadrons.org>